AD Issued on Sandel TAWS/RMI

September 25 is the effective date for an AD aimed at owners of the Sandel ST3400 terrain awareness and warning system/radio magnetic indicator (TAWS/RMI). The directive (AD 2006-16-18) was prompted by a report of in-flight bearing error caused by input signal fault and software error. Operators are required to install new software and placard the unit until the upgrade is installed.